​​点击打开链接​​

因为图中每一个点被访问过后权值就消失了 所以不能用最短路直接求 先缩点 然后得一DAG图 求最长路即可

if语句后边多了一个分号 调了一晚上 真的舒服

#include <cstdio>
#include <queue>
#include <stack>
#include <cstring>
#include <algorithm>
using namespace std;
#define N 0x3f3f3f3f

struct node1
{
    int v;
    int next;
};

struct node2
{
    int v;
    int w;
    int next;
};

stack <int> stk;
queue <int> que;
node1 edge1[20010];
node2 edge2[20010];
int first1[2010],first2[2010],per[2010],dfn[2010],low[2010],book[2010],belong[2010],val[2010];
int pre[2010],dis[2010];
int n,m,num,tot;
char mp[50][50];

void addedgeI(int u,int v)
{
    edge1[num].v=v;
    edge1[num].next=first1[u];
    first1[u]=num++;
    return;
}

void addedgeII(int u,int v,int w)
{
    edge2[num].v=v;
    edge2[num].w=w;
    edge2[num].next=first2[u];
    first2[u]=num++;
    return;
}

void build()
{
    int next[2][2]={0,1,1,0};
    int i,j,k,tx,ty,cnt;
    memset(first1,-1,sizeof(first1));
    num=0,cnt=0;
    for(i=0;i<n;i++)
    {
        for(j=0;j<m;j++)
        {
            for(k=0;k<2;k++)
            {
                tx=i+next[k][0];
                ty=j+next[k][1];
                if(tx<0||tx>n-1||ty<0||ty>m-1||mp[tx][ty]=='#') continue;
                addedgeI(i*m+j+1,tx*m+ty+1);
            }
            if('0'<=mp[i][j]&&mp[i][j]<='9')
            {
                per[i*m+j+1]=mp[i][j]-'0';
            }
            else if(mp[i][j]=='#')
            {
                per[i*m+j+1]=-1;
            }
            else
            {
                per[i*m+j+1]=0;
                cnt++;
                if(pre[cnt]!=-1) addedgeI(i*m+j+1,pre[cnt]);
            }
        }
    }
    return;
}

void dfs(int cur)
{
    int i,v;
    stk.push(cur);
    num++;
    dfn[cur]=num,low[cur]=num,book[cur]=1;
    for(i=first1[cur];i!=-1;i=edge1[i].next)
    {
        v=edge1[i].v;
        if(!dfn[v])
        {
            dfs(v);
            low[cur]=min(low[cur],low[v]);
        }
        else if(book[v])
        {
            low[cur]=min(low[cur],dfn[v]);
        }
    }
    if(dfn[cur]==low[cur])
    {
        tot++;
        while(!stk.empty())
        {
            v=stk.top();
            stk.pop();
            book[v]=0;
            belong[v]=tot;
            val[tot]+=per[v];
            if(v==cur) break;
        }
    }
    return;
}

void tarjan()
{
    int i,u,v;
    while(!stk.empty()) stk.pop();
    memset(dfn,0,sizeof(dfn));
    memset(low,0,sizeof(low));
    memset(book,0,sizeof(book));
    memset(belong,0,sizeof(belong));
    memset(val,0,sizeof(val));
    num=0,tot=0;
    for(i=1;i<=n*m;i++)
    {
        if(!dfn[i]&&per[i]!=-1) dfs(i);
    }
    memset(first2,-1,sizeof(first2));
    num=0;
    for(u=1;u<=n*m;u++)
    {
        for(i=first1[u];i!=-1;i=edge1[i].next)
        {
            v=edge1[i].v;
            if(belong[u]!=belong[v])
            {
                addedgeII(belong[u],belong[v],val[belong[v]]);
            }
        }
    }
    return;
}

int spfa()
{
    int i,u,v,w,maxx;
    while(!que.empty()) que.pop();
    for(i=1;i<=tot;i++)
    {
        dis[i]=-N;
        book[i]=0;
    }
    que.push(belong[1]);
    dis[belong[1]]=val[belong[1]];
    book[belong[1]]=1;

    while(!que.empty())
    {
        u=que.front();
        que.pop();
        book[u]=0;
        for(i=first2[u];i!=-1;i=edge2[i].next)
        {
            v=edge2[i].v,w=edge2[i].w;
            if(dis[v]<dis[u]+w)
            {
                dis[v]=dis[u]+w;
                if(!book[v])
                {
                    que.push(v);
                    book[v]=1;
                }
            }
        }
    }
    maxx=0;
    for(i=1;i<=tot;i++)
    {
        maxx=max(maxx,dis[i]);
    }
    return maxx;
}

int main()
{
    int t,i,j,cnt,x,y;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d%d",&n,&m);
        for(i=0;i<n;i++)
        {
            scanf("%s",mp[i]);
        }
        cnt=0;
        for(i=0;i<n;i++)
        {
            for(j=0;j<m;j++)
            {
                if(mp[i][j]=='*') cnt++;
            }
        }
        for(i=1;i<=cnt;i++)
        {
            scanf("%d%d",&x,&y);
            if(mp[x][y]!='#') pre[i]=x*m+y+1;
            else pre[i]=-1;
        }
        build();
        tarjan();
        printf("%d\n",spfa());
    }
    return 0;
}